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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
Tunnel and Underground Space
Journal Basic Information
Journal DOI :
Korean Society for Rock Mechanics
Editor in Chief :
Volume & Issues
Volume 22, Issue 6 - Dec 2012
Volume 22, Issue 5 - Oct 2012
Volume 22, Issue 4 - Aug 2012
Volume 22, Issue 3 - Jun 2012
Volume 22, Issue 2 - Apr 2012
Volume 22, Issue 1 - Feb 2012
Selecting the target year
Stability Assessment of Abandoned Gangway for Commercial Utilization of Services
SunWoo, Choon ; Chung, So-Keul ; Lee, Yun-Su ; Kang, Sang-Soo ; Kang, Jung-Seok ;
Tunnel and Underground Space, volume 22, issue 5, 2012, Pages 297~309
DOI : 10.7474/TUS.2012.22.5.297
The stability assessment of abandoned gangway for the purpose of services was performed. Among the many factors that affect the stability of openings, the span of the opening in a given rock mass condition provides an important element of design. In this paper, the stability of gangway was assessed by the critical span curves proposed by Lang, the modified Mathews'stability graph method and using support measures of the Q system. In the evaluation of stability as a whole the gangway is considered as stable. But the rockfalls of wedge-shaped blocks were expected in the area in which the horizontal joints of low angle appear. The support measures such as local rock bolts are required to use for commercial purposes of the abandoned gangway. And entrance section may require the particular attention as unstable section. Since there are so many spalling due to bad blasting in the roof and sidewall of gangway, the scaling operations should be followed primarily.
A Case Study on the Design and Construction of a 2-arch Tunnel with Varying Section
Choi, Jae-Jin ; Park, Yeon-Jun ; Kim, Si-Keun ; Park, Jae-Hyun ;
Tunnel and Underground Space, volume 22, issue 5, 2012, Pages 310~320
DOI : 10.7474/TUS.2012.22.5.310
This paper describes the design and construction of a 2-arch tunnel with varying section. This new design has advantages of 2-arch tunnels, which is rather expensive, but is still economically competitive compared to parallel tunnels. Economic analysis was also conducted. To secure the stability of the varying section tunnel, excavated part was reinforced by tie-bolts and RRS, and 2-arch part was supported by EPS blocks and concrete walls. Stability of the pillar was theoretically analyzed and also examined by numerical simulations for various widths. Displacement monitoring was conducted and results were compared with numerical results. Economic analysis showed reductions in construction cost and period by 11% and 10 months respectively.
Changes on Physical Property of Ilmenite due to Microorganism
Park, Young Ho ; Kang, Dae Wan ; Kang, Seong-Seung ;
Tunnel and Underground Space, volume 22, issue 5, 2012, Pages 321~329
DOI : 10.7474/TUS.2012.22.5.321
Laboratory tests for measuring absorption, porosity, P-wave velocity and uniaxial compressive strength (UCS) were performed to examine weathering characteristics of ilmenite by microorganism. Physical property changes were quantitatively estimated with comparing culture period on the condition of abiotic oxidation without microorganism and biooxidation with microorganism. As a result, the measured pH during 45 days was distributed in the range from 3.82 to 4.26, on the other hand, biooxidation showed the range from 2.20 to 2.57. The measured absorption according to microorganism and culture period represented 0.052% at final stage in the case of abiotic oxidation and 0.073% in the case of biooxidation. Porosity showed 0.206% at final stage in the case of abiotic oxidation and 0.281% in the case of biooxidation. In general, the values by biooxidation showed higher than that by abiotic oxidation. Change range of P-wave velocity with culture period showed that the measured value as 1410 m/s at final stage in the case of biooxidation was lower than 1886 m/s of that in the case of abiotic oxidation. The UCS was decreased with increasing culture period in all specimens and represented 241.1 MPa at final stage in the case of abiotic oxidation and 140.0 MPa in the case of bioxidation. In conclusion, it implies that influence of physical property on ilmenite by biooxidation related with microorganism was larger than that by abiotic oxidation.
A Study on the Correlation between Uniaxial Compressive Strength and Point Load Strength Index of Limestone of Imgye Area
Kim, Gyoung Man ; Kim, Dae Hoon ; Kang, Jung Seock ; Kang, Sang Soo ; Baek, Hwanjo ;
Tunnel and Underground Space, volume 22, issue 5, 2012, Pages 330~338
DOI : 10.7474/TUS.2012.22.5.330
Though the uniaxial compressive strength (UCS) of rock material is one of the key properties for rockmass characterization purposes, core samples for the test cannot always be obtained from the field. Indirect tests such as the point load test (PLT) can be a useful alternative. In this study, correlation between the UCS and the point load strength index of limestone of Imgye area was analyzed, and the linear regression equation obtained from regression analysis of two variables was suggested. The results of this study were also compared with previous studies on limestone. It was suggested that conversion factors for the same rock type from diverse areas in Korea may have different values, and more data should be obtained to increase the accuracy of regression analysis.
Experimental Study on Deformation and Failure Behavior of Limestones under Dynamic Loadings
Kang, Myoung-Soo ; Kang, Hyeong-Min ; Kim, Seung-Kon ; Cheon, Dae-Sung ; Kaneko, Katsuhiko ; Cho, Sang-Ho ;
Tunnel and Underground Space, volume 22, issue 5, 2012, Pages 339~345
DOI : 10.7474/TUS.2012.22.5.339
Information on the deformation behavior and fracture strength of rocks subjected to dynamic loadings is important to stability analyses of underground openings underground vibration due to rock blasts, earthquakes and rock bursts. In this study, Split Hopkinson Pressure Bar (SHPB) system was applied to estimate dynamic compressive and tensile fracture strengths of limestone and also examine deformation behavior of limestones under dynamic loadings. A micro-focus X-ray CT scanner was used to observe non-destructively inside the impacted limestone specimens. From the dynamic tests, it was revealed that the limestone have over 140MPa dynamic compressive strength and the strain-rate dependency of the strength. Dynamic Brazilian tensile strength of the limestone exceeds 21MPa and shows over 3 times static Brazilian tensile strength.
Experimental Study on the Elastic Constants of A Transversely Isotropic Rock by Multi-Specimen Compression Tests Report 2 - Statistical Evaluation and Determination of True Values of Elastic Constants
Park, Chulwhan ; Park, Chan ; Jung, Yong-Bok ;
Tunnel and Underground Space, volume 22, issue 5, 2012, Pages 346~353
DOI : 10.7474/TUS.2012.22.5.346
Multi-specimen uniaxial compression test has been carried out in order to find the method to determine the five independent elastic constants from a single standard specimen of a transversely isotropic rock. Total 35 specimens of 7 different angles from a large block of rhyolite presenting the flow structure obviously are used in tests. This second report is to focus on the statistical evaluation of measured strains and analyzed elastic constants. And the determination of their true or near-true values is discussed. As the result of RSD analysis, it turns out that the reliability of measured strains is sufficiently obtained and Saint-Venant approximation is well applicable except 15 degree angled specimen in tests. RSD is decreasing on the increase of the angle of anisotropy. This tendency may be caused not only by the decreasing of the deviation of measured strains, but also by the better applicability of Saint-Venant approximation on the increase of angle. It can be concluded that the analyzed values are considered the near-true ones of five independent constants on the high reliability. But the variation of the apparent Young's modulus expected by these values is not proved to match the measured tendency. It is inferred that the factor to decrease the apparent Young's modulus and/or to increase the shear strain, is present in the test or in the nature of the anisotropy in consideration of this inconsistency.
The Mechanical Properties of Limestones Distributed in Jecheon
Kim, Jong Woo ; Kim, Min Sik ; Kim, Pyoung Gi ; Nor, Seung Jae ; Park, Chan ; Jo, Young Do ; Park, Sam Gyu ;
Tunnel and Underground Space, volume 22, issue 5, 2012, Pages 354~364
DOI : 10.7474/TUS.2012.22.5.354
In order to evaluate the physical properties of rock which might serve as a database for both mining and civil works, a lot of laboratory tests for Jecheon limestones were conducted to find unit weight, absorption ratio, porosity, elastic wave velocity, uniaxial compressive strength, Young's modulus, poisson's ratio, tensile strength, shore hardness, friction angle and cohesion. On investigation of the mechanical properties of both the gray limestone and the clayey limestone distributed in the studied region, the clayey limestone turned out to have more weak mechanical properties which might come from low unit weight, high absorption ratio and high porosity of rocks. The failure criteria of Jecheon limestones were discussed by means of both Mohr-Coulomb criterion and Hoek-Brown criterion. Regression analyses of the physical properties obtained from a lot of laboratory tests were also conducted by means of both linear and multiple regression analyses.
A Study on the Behaviour of Smoke Spread Caused by Vehicle Fire in a Road Tunnel
Yoon, Yong-Kyun ; Ju, Eun-Hye ;
Tunnel and Underground Space, volume 22, issue 5, 2012, Pages 365~372
DOI : 10.7474/TUS.2012.22.5.365
This paper aims to evaluate the effects that presence, installation number and capacity of ventilation vent and presence of multiple fire sources have on the behaviour of smoke temperature induced by vehicle fire in road tunnel. Six types of scenarios were assumed and FDS was ran to simulate them. As the number of ventilation vents increases, the smoke temperature are calculated to be reduced, but it is shown that effects exerted by two ventilation vents are almost similar to ones by three ventilation vents. Capacity of ventilation vent has a greater impact on the reduction of smoke temperature than installation number of ventilation vents. Smoke temperatures computed for all scenarios except for scenario No. 1 (without ventilation vent) and scenario No. 6 (with multiple fire sources) above fire source are analyzed to be under
and it means that the radiation of smoke layer above fire source doesn't induce the ignition of materials around fire source.